title: Time to clearance of Chlamydia trachomatis ribosomal RNA in women treated for chlamydial infection.
abstract: BACKGROUND
  The dynamics of chlamydia clearance after treatment administration for chlamydial urogenital infection are unknown. We estimated the time to clearance of Chlamydia trachomatis (CT) ribosomal RNA (rRNA) after administration of azithromycin for cervical chlamydial infection using APTIMA Combo 2 (Gen-Probe, Inc., San Diego, CA, USA).
  
  
  METHODS
  A total of 115 women diagnosed with urogenital chlamydial infection, defined as a positive APTIMA urine or endocervical specimen, were enrolled in the present study. Vaginal swabs on the day of treatment (Day 0) and on Days 3, 7, 10 and 14 after treatment with 1 g of azithromycin were self-obtained by participants. Specimens were tested in a single laboratory. Our analysis was limited to women who were CT-confirmed by vaginal swab at baseline, who returned all follow-up swabs, and who reported sexual abstinence during the follow-up period (n = 61).
  
  
  RESULTS
  Among 61 participants, 48 (79%) had a negative APTIMA at Day 14. Subjects with a negative APTIMA at each time-point were as follows: 0/61 (0%) on Day 0, 7/61 (12%) on Day 3, 28/61 (46%) on Day 7, 40/61 (66%) on Day 10, and 48/61 (79%) on Day 14. Multiple linear regression analysis predicted time to clearance at 17 days (95% confidence interval, 16-18 days) after administration of azithromycin. Seventeen of the 94 participants (18.1%) who screened positive for chlamydia had a negative vaginal swab on Day 0, indicating possible spontaneous clearance of CT.
  
  
  CONCLUSIONS
  After treatment, CT rRNA declined with time. As rRNA was still detectable in 21% of the women 14 days after treatment, APTIMA should not be used as a test-of-cure in the 14-day period following azithromycin administration.
authors.affiliation: Stanford University School of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford, CA 94305-5107, USA.
authors.forename: Cybèle A
authors.initials: CA
authors.lastname: Renault
authors.forename: Dennis M
authors.initials: DM
authors.lastname: Israelski
authors.forename: Vivian
authors.initials: V
authors.lastname: Levy
authors.forename: Bruce K
authors.initials: BK
authors.lastname: Fujikawa
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Kellogg
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Klausner
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D017963:Azithromycin / Q000008:administration & dosage / Q000494:pharmacology*; D002690:Chlamydia Infections / Q000188:drug therapy*; D002692:Chlamydia trachomatis / Q000187:drug effects* / Q000302:isolation & purification; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D011446:Prospective Studies; D012329:RNA, Bacterial / Q000187:drug effects* / Q000235:genetics; D012335:RNA, Ribosomal / Q000187:drug effects; D011933:Reagent Kits, Diagnostic; D014621:Vagina / Q000382:microbiology; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D011933:Reagent Kits, Diagnostic; D017963:Azithromycin